Method for transreceiving signal and apparatus for same

ABSTRACT

A method for receiving a signal by a user equipment in a wireless communication system, the method includes detecting downlink control information (DCI) within a subframe indicated by a radio resource control (RRC) layer signal; and receiving, based on the DCI, a data signal in K consecutive subframes other than at least one subframe corresponding to a specific subframe, wherein K is greater than 1, wherein the specific subframe includes at least a subframe transmitting a physical broadcast channel (PBCH), a subframe transmitting a synchronization signal, and a subframe transmitting system information, and wherein the DCI is not applied to the at least one subframe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/760,971 flied on Jul. 14, 2015 (now, U.S. Pat. No. 9,706,567 issuedon Jul. 11, 2017), which is the National Phase of PCT InternationalApplication No. PCT/KR2014/001038 flied on Feb. 6, 2014, which claimsthe benefit under 35 U.S.C. § 119(e) to U.S. Provisional ApplicationNos. 61/837,150 filed on Jun. 19, 2013, 61/821,252 filed on May 9, 2013,61/808,616 filed on Apr. 4, 2013, 61/786,554 filed on Mar. 15, 2013 and61/761,239 filed on Feb. 6, 2013, all of which are hereby expresslyincorporated by reference into the present application.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a wireless communication system, morespecifically, relates to a method for scheduling a plurality of datasignals and an apparatus therefor.

Discussion of the Related Art

Wireless communication systems are widely developed to provide variouskinds of communication services including audio communications, datacommunications and the like. Generally, a wireless communication systemis a kind of a multiple access system capable of supportingcommunications with multiple users by sharing available system resources(e.g., bandwidth, transmission power, etc.). For instance, multipleaccess systems include CDMA (code division multiple access) system, FDMA(frequency division multiple access) system, TDMA (time divisionmultiple access) system, OFDMA (orthogonal frequency division multipleaccess) system, SC-FDMA (single carrier frequency division multipleaccess) system and the like.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method and apparatusfor effectively transmitting and receiving a signal in a wirelesscommunication system.

Another object of the present invention is to provide a signaling methodand apparatus for effectively scheduling a plurality of data signals ina wireless communication system.

Another object of the present invention is to provide a method andapparatus for effectively allocating a hybrid automatic repeat andrequest (HARQ) process number when a plurality of data signals isscheduled using one control information in a wireless communicationsystem.

Another object of the present invention is to provide a method andapparatus for effectively applying control information when controlinformation for a single data signal is detected/received in a timeperiod scheduled by control information for scheduling a plurality ofdata signals in a wireless communication system.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

In an aspect of the present invention, provided herein is a method forreceiving a signal by a user equipment in a wireless communicationsystem, the method comprising: receiving downlink control informationcomprising scheduling information about K subframes through a physicaldownlink control channel, wherein K is greater than 1, wherein when atleast one subframe among the K subframes corresponds to a specificsubframe, the scheduling information is not applied to the at least onesubframe, and wherein the specific subframe includes at least a subframeconfigured for a multicast-broadcast single-frequency network (MBSFN),or a subframe configured to receive a physical multicast channel (PMCH),or a subframe configured to transmit a positioning reference signal(PRS), or a subframe comprising a downlink period, a guard period, andan uplink period.

In another aspect of the present invention, provided herein is a userequipment of a wireless communication system, the user equipmentcomprising: a radio frequency (RF) unit; and a processor, wherein theprocessor is configured to receive downlink control informationcomprising scheduling information about K subframes through a physicaldownlink control channel by the RF unit, wherein K is greater than 1,wherein when at least one subframe among the K subframes corresponds toa specific subframe, the scheduling information is not applied to the atleast one subframe, and wherein the specific subframe includes at leasta subframe configured for a multicast-broadcast single-frequency network(MBSFN), or a subframe configured to receive a physical multicastchannel (PMCH), or a subframe configured to transmit a positioningreference signal (PRS), or a subframe comprising a downlink period, aguard period, and an uplink period.

Preferably, the specific subframe may further include a subframe inwhich a physical broadcast channel (PBCH) signal is transmitted, or asubframe configured to transmit system information, or a subframeconfigured to transmit a paging signal, or a subframe configured totransmit a synchronization signal, or a subframe configured to performsemi-persistent scheduling, or a subframe configured to enabletransmission of a physical random access channel (PRACH), or a subframeconfigured not to transmit a demodulation reference signal (DMRS), or asubframe configured to transmit a channel state information-referencesignal (CSI-RS).

Preferably, the scheduling information may be applied to K subframesexcept for the at least one subframe.

Preferably, the scheduling information may be applied to M subframesexcept for the at least one subframe, and M may be smaller than K.

Preferably, the downlink control information may further includeinformation indicating a subframe to which the scheduling is not appliedamong the K subframes, and the specific subframe may further include asubframe indicated such that the scheduling information is not appliedthrough the downlink control information.

Preferably, the downlink control information may further includeinformation indicating whether the downlink control information isapplied to the K subframes or applied to only a subframe in which thedownlink information is received.

Preferably, M data signals may be received using the schedulinginformation, M may be equal to or smaller than K, and different hybridautomatic repeat request (HARQ) process numbers may be allocated to theM data signals.

Preferably, the HARQ process number may be pre-allocated through highlayer signaling.

Preferably, the downlink control information may further include a fieldindicating the HARQ process number, the HARQ process number may beconsecutively and increasingly allocated from a value of the field andis determined by applying a modulo operation using the allocated valueas a specific value, and the specific value may be a maximum number ofHARQ processes or a maximum number of HARQ process receive buffer,supported by the user equipment.

Preferably, the downlink control information may further include indexinformation indicating the HARQ process number, and the index uniquelydetermines a set of the HARQ process number.

Preferably, when a set of the HARQ process number is {k_(i)}_(i=0)^(K−1), the index information may be given according to

${r = {\sum\limits_{i = 0}^{K - 1}\left\langle \begin{matrix}{{\max\;{HARQp}} - k_{i}} \\{K - i}\end{matrix} \right\rangle}},$and maxHARQp is a maximum number of HARQ processes or a maximum numberof HARQ process receive buffers supported by the user equipment,

$\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle = \left\{ {\begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix},{{and}\mspace{14mu}\begin{pmatrix}x \\y\end{pmatrix}}} \right.$is a binominal coefficient.

Preferably, blind decoding (BD) may not be performed on the K subframesto which the downlink control information is applied.

Preferably, when other downlink control information is detected in onesubframe of the K subframes, a data signal may be received according tothe other downlink control information with respect to the one subframe.

Preferably, an operation of receiving a data signal according to thedownlink control information may be omitted with respect to a subframeafter the one subframe in the K subframes.

According to the present invention, a signal may be effectivelytransmitted and received in a wireless communication system.

According to the present invention, a plurality of data signals may beeffectively scheduled in a wireless communication system.

According to the present invention, a hybrid automatic repeat andrequest (HARQ) process number may be effectively allocated when aplurality of data signals is scheduled using one control information ina wireless communication system.

In addition, according to the present invention, control information maybe effectively applied when control information for a single data signalis detected/received in a time period scheduled by control informationfor scheduling a plurality of data signals in a wireless communicationsystem.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 illustrates layers of a radio protocol.

FIG. 2 illustrates physical channels and a general method fortransmitting signals on the physical channels in the LTE(-A) system.

FIG. 3 illustrates a structure of a radio frame used in the LTE(-A)system.

FIG. 4 illustrates a resource grid of one downlink slot.

FIG. 5 illustrates a downlink subframe structure.

FIG. 6 illustrates an example of allocating E-PDCCH in a subframe.

FIG. 7 illustrates a structure of an uplink subframe.

FIG. 8 illustrates a multi-SF scheduling method according to the presentinvention.

FIG. 9 illustrates a flowchart of a method for receiving data accordingto the present invention.

FIG. 10 illustrates an example of allocating HARQ process numbers usinga combinatorial index.

FIG. 11 illustrates an example of allocating a HARQ process when anomitted SF is present.

FIG. 12 illustrates a base station and a user equipment to which thepresent invention is applicable.

DETAILED DESCRIPTION OF THE INVENTION

The following embodiments of the present invention may be applied to avariety of wireless access technologies such as code division multipleaccess (CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), single carrier frequency division multiple access (SC-FDMA),and the like. CDMA may be embodied through wireless (or radio)technology such as universal terrestrial radio access (UTRA) orCDMA2000. TDMA may be embodied through wireless (or radio) technologysuch as global system for mobile communication (GSM)/general packetradio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMAmay be implemented by wireless (or radio) technology such as Instituteof Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802-20, and evolved UTRA (E-UTRA). UTRA is a partof universal mobile telecommunications system (UMTS). 3^(rd) generationpartnership project (3GPP) long term evolution (LTE) is a part of E-UMTS(Evolved UMTS), which uses E-UTRA. LTE-Advanced (LTE-A) is an evolvedversion of 3GPP LTE.

For clarity of explanations, the following description focuses on 3GPPLTE(-A) system. However, technical features of the present invention arenot limited thereto. Further, a particular terminology is provided forbetter understanding of the present invention. However, such aparticular terminology may be changed without departing from thetechnical spirit of the present invention. For example, the presentinvention may be applied to a system in accordance with a 3GPP LTE/LTE-Asystem as well as a system in accordance with another 3GPP standard,IEEE 802.xx standard, or 3GPP2 standard.

In a wireless access system, a UE may receive information from a BS indownlink (DL) and transmit information in uplink (UL). The informationtransmitted or received by the UE may include data and various controlinformation. In addition, there are various physical channels accordingto the type or use of the information transmitted or received by the UE.

In the present invention, a base station (BS) generally refers to afixed station that performs communication with a UE and/or another BS,and exchanges various kinds of data and control information with the UEand another BS. The base station (BS) may be referred to as an advancedbase station (ABS), a node-B (NB), an evolved node-B (eNB), a basetransceiver system (BTS), an access point (AP), a processing server(PS), a transmission point (TP), etc. In the present invention, a BS maybe interchangeably referred to as an eNB.

FIG. 1 illustrates layers of a radio protocol.

The physical layer (PHY) which is a first layer provides informationtransfer services to the upper layers using a physical channel. The PHYlayer is connected to the upper medium access control (MAC) layerthrough a transport channel, and data between the MAC layer and the PHYlayer is transferred through the transport channel. In this case, thetransport channel is roughly divided into a dedicated transport channeland a common transport channel based on whether or not the channel isshared. Furthermore, data is transferred between different PHY layers,i.e., between PHY layers at transmitter and receiver sides.

A second layer may include various layers. The medium access control(MAC) layer serves to map various logical channels to various transportchannels, and also performs logical channel multiplexing for mappingseveral logical channels to one transport channel. The MAC layer isconnected to a radio link control (RLC) layer, which is an upper layer,through a logical channel, and the logical channel is roughly dividedinto a control channel for transmitting control plane information and atraffic channel for transmitting user plane information according to thetype of information to be transmitted.

The RLC layer of the second layer manages segmentation and concatenationof data received from an upper layer to appropriately adjusts a datasize such that a lower layer can send data to a radio section. Also, theRLC layer provides three operation modes such as a Transparent Mode(TM), an Un-acknowledged Mode (UM), and an Acknowledged Mode (AM) so asto guarantee various Quality of Services (QoS) required by each RadioBearer (RB). In particular, AM RLC performs a retransmission functionthrough an ARQ function for reliable data transmission.

A radio resource control (RRC) layer located at the uppermost portion ofa third layer is only defined in the control plane. The RRC layerperforms a role of controlling logical channels, transport channels, andphysical channels in relation to configuration, re-configuration, andrelease of radio bearers. Here, the radio bearer denotes a logical pathprovided by the first and the second layers for transferring databetween the UE and the UTRAN. In general, the configuration of the radiobearer refers to a process of stipulating the characteristics ofprotocol layers and channels required for providing a specific service,and setting each of the detailed parameter and operation methodsthereof. The radio bearer is divided into a signaling radio bearer (SRB)and a data radio bearer (DRB), wherein the SRB is used as a path fortransmitting RRC messages in the control plane while the DRB is used asa path for transmitting user data in the user plane.

In a wireless access system, a user equipment (UE) may receiveinformation from a base station (BS) in downlink (DL) and transmitinformation in uplink (UL). The information transmitted or received bythe UE may include general data information and various controlinformation. In addition, there are various physical channels accordingto the type or use of the information transmitted or received by the UE.

FIG. 2 illustrates physical channels and a general method fortransmitting signals on the physical channels in the LTE(-A) system.

When a UE is powered on or enters a new cell, the UE performs initialcell search in step S201. The initial cell search involves acquisitionof synchronization to a base station. To this end, the UE synchronizesits timing to the base station and acquires information such as a cellidentifier (ID) by receiving a primary synchronization channel (P-SCH)and a secondary synchronization channel (S-SCH) from the base station.Then the UE may acquire broadcast information in the cell by receiving aphysical broadcast channel (PBCH) from the base station. During theinitial cell search, the UE may monitor a DL channel state by receivinga downlink reference signal (DL RS).

After the initial cell search, the UE may acquire more detailed systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving a physical downlink shared channel (PDSCH) based oninformation of the PDCCH in step S202.

To complete access to the base station, the UE may perform a randomaccess procedure such as steps S203 to S206 with the base station. Tothis end, the UE may transmit a preamble on a physical random accesschannel (PRACH) (S203) and may receive a response message to thepreamble on a PDCCH and a PDSCH associated with the PDCCH (S204). In thecase of a contention-based random access, the UE may additionallyperform a contention resolution procedure including transmission of anadditional PRACH (S205) and reception of a PDCCH signal and a PDSCHsignal corresponding to the PDCCH signal (S206).

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the base station (S207) and transmit a physical uplink sharedchannel (PUSCH) and/or a physical uplink control channel (PUCCH) to thebase station (S208), in a general UL/DL signal transmission procedure.Information that the UE transmits to the base station is referred to asUplink Control Information (UCI). The UCI includes hybrid automaticrepeat and request acknowledgement/negative acknowledgement(HARQ-ACK/NACK), scheduling request (SR), channel state information(CSI), etc. The CSI includes channel quality indicator (CQI), precodingmatrix indicator (PMI), rank indication (RI), etc. UCI is generallytransmitted on a PUCCH periodically. However, if control information andtraffic data should be transmitted simultaneously, they may betransmitted on a PUSCH. In addition, the UCI may be transmittedaperiodically on the PUSCH, upon receipt of a request/command from anetwork.

FIG. 3 illustrates a structure of a radio frame used in the LTE(-A)system. In a cellular OFDM radio packet communication system,uplink/downlink data packet transmission is performed in the unit of asubframe (SF), and one subframe is defined as a predetermined durationincluding a plurality of OFDM symbols. The LTE(-A) system supports atype-1 radio frame structure applicable to frequency division duplex(FDD) and a type-2 radio frame structure applicable to time divisionduplex (TDD).

FIG. 3(a) shows the structure of the type-1 radio frame. A downlinkradio frame includes 10 subframes and one subframe includes two slots ina time domain. A time required to transmit one subframe is referred toas a transmission time interval (TTI). For example, one subframe has alength of 1 ms and one slot has a length of 0.5 ms. One slot includes aplurality of OFDM symbols in a time domain and includes a plurality ofresource blocks (RBs) in a frequency domain. In the LTE(-A) system,since OFDM is used in downlink, an OFDM symbol indicates one symbolduration. In the LTE(-A) system, since SC-FDMA is used in uplink, anOFDM symbol may be referred to as an SC-FDMA symbol in the presentspecification, and also may be collectively referred to as a symbolduration. A resource block (RB) as a resource assignment unit mayinclude a plurality of consecutive subcarriers in one slot. A subframeused for a downlink communication is referred to as a downlink subframe,and may be represented by DL SF. A subframe used for an uplinkcommunication is referred to as an uplink subframe, and may berepresented by UL SF.

The length of one symbol duration (or the number of OFDM symbolsincluded in one slot) may vary according to a configuration of cyclicprefix (CP). The cyclic prefix refers to repeating a portion of symbol(e.g. the last portion of symbol) or the entire symbol and placing therepeated portion in front of the symbol. The cyclic prefix (CP) includesan extended CP and a normal CP. For example, if OFDM symbols areconfigured by the normal CP, the number of OFDM symbols included in oneslot may be 7. In case of the extended CP, for example, the number ofOFDM symbols included in one slot may be 6.

FIG. 3(b) illustrates a structure of the type-2 radio frame. The type-2radio frame includes two half frames, and each half frame includes fivesubframes, a downlink period (e.g. a downlink pilot time slot or DwPTS),a guard period (GP) and an uplink period (e.g. an uplink pilot time slotor UpPTS). One subframe includes two slots. For example, the downlinkperiod (e.g., DwPTS) is used for initial cell search, synchronization orchannel estimation of a UE. For example, the uplink period (e.g., UpPTS)is used for channel estimation of a BS and uplink transmissionsynchronization of a UE. For example, the uplink period (e.g., UpPTS)may be used to transmit a sounding reference signal (SRS) for channelestimation in a base station and to transmit a physical random accesschannel (PRACH) that carriers a random access preamble for uplinktransmission synchronization. The guard period is used to eliminateinterference generated in uplink due to multi-path delay of a downlinksignal between uplink and downlink. Table 1 shows an example of anuplink-downlink (UL-DL) configuration of subframes within a radio framein a TDD mode.

TABLE 1 Downlink- Uplink- to-Uplink downlink Switch-point Subframenumber configuration periodicity 0 1 2 3 4 5 6 7 8 9 0  5 ms D S U U U DS U U U 1  5 ms D S U U D D S U U D 2  5 ms D S U D D D S U D D 3 10 msD S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D DD D 6  5 ms D S U U U D S U U D

In Table 1 above, D represents a downlink subframe (DL SF), Iirepresents an uplink subframe (UL SF), and S represents a specialsubframe. The special subframe includes a downlink period (e.g. DwPTS),a guard period (e.g. GP), and an uplink period (e.g. UpPTS). Table 2shows an example of a special subframe configuration.

TABLE 2 Normal Extended cyclic prefix in downlink cyclic prefix indownlink UpPTS UpPTS Special Normal Extended Normal Extended subframecyclic prefix cyclic prefix cyclic prefix cyclic prefix configurationDwPTS in uplink in uplink DwPTS in uplink in uplink 0  6592 · T_(s) 2192· T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 1 19760 ·T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600· T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 · T_(s) 5  6592· T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 · T_(s) 23040 ·T_(s) 7 21952 · T_(s) — — — 8 24144 · T_(s) — — —

The above-described radio frame structure is exemplary. Thus, the numberof subframes in a radio frame, the number of slots in a subframe, or thenumber of symbols in a slot may be modified in various ways.

FIG. 4 illustrates a resource grid of one downlink slot.

Referring to FIG. 4, a downlink slot includes a plurality of OFDMsymbols in the time domain. One downlink slot may include 7 OFDM symbolsand one resource block (RB) may include 12 subcarriers in the frequencydomain. An example as illustrated in FIG. 4 may be applied to a normalCP case, while one downlink slot may include 6 OFDM symbols in the timedomain in case of an extended CP case. Each element of the resource gridis referred to as a Resource Element (RE). An RB includes 12×7 REs. Thenumber of RBs in a downlink slot, N_(DL) depends on a downlinktransmission bandwidth. The structure of an uplink slot may have thesame structure as a downlink slot.

FIG. 5 illustrates a downlink subframe structure.

Referring to FIG. 5, a maximum of three (four) OFDM symbols located in afront portion of a first slot within a subframe correspond to a controlregion to which a control channel is allocated. The remaining OFDMsymbols correspond to a data region to which a physical downlink sharedchancel (PDSCH) is allocated. A basic resource unit of the data regionis RB. Examples of downlink control channels used in the LTE(-A) systeminclude a physical control format indicator channel (PCFICH), a physicaldownlink control channel (PDCCH), a physical hybrid ARQ indicatorchannel (PHICH), etc.

PCFICH is transmitted at the first OFDM symbol of a subframe and carriesinformation regarding the number of OFDM symbols used for transmissionof control channels within the subframe. The PCFICH is composed of fourresource element groups (REGs) each of which is uniformly distributed ina control region based on a cell ID. The PCFICH indicates a value of 1to 3 (or 2 to 4) and is modulated using quadrature phase shift keying(QPSK).

PDCCH carries a transmission format or resource allocation informationof downlink shared channel (DL-SCH), a transmission format or resourceallocation information of uplink shared channel (UL-SCH), paginginformation on paging channel (PCH), system information on DL-SCH,resource allocation information of an upper layer control message suchas random access response transmitted on PDSCH, a set of Tx powercontrol commands for individual UEs within a UE group, Tx power controlcommand, activation indication information of Voice over IP (VoIP), etc.The PDCCH is allocated in the first n OFDM symbols (hereinafter, acontrol region) of a subframe. Here, n is an integer equal to or greaterthan 1 and is indicated by the PCFICH. Control information transmittedthrough the PDCCH is referred to as downlink control information (DCI).DCI format is defined as formats 0, 3, 3A, and 4 for uplink and definedas formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, and 2D for downlink. Forexample, DCI format may selectively include exemplary fields shown inTable 3. In Table 3, a bit size of each information field is anon-limiting example.

TABLE 3 Field Bit(s) Flag for determining DCI format 0/1 A 1 Hoppingflag 1 RB assignment ┌log₂(N_(RB) ^(UL)(N_(RB) ^(UL) + 1)/2)┐ MCS(Modulation and coding scheme) 5 and RV (Redundancy Version) NDI (NewData Indicator) 1 TPC (Transmit Power Control) command 2 for scheduledPUSCH Cyclic shift for DM RS 3 UL index (TDD) 2 CQI request 1

The flag field is an information field for identifying between DCIformat 0 and DCI format 1A. That is, DCI format 0 and DCI format 1A havethe same payload size and are identified by the flag field. The bit sizeof the resource block allocation and hopping resource allocation fieldmay vary according to hopping PUSCH or non-hopping PUSCH. The resourceblock allocation and hopping resource allocation field for thenon-hopping PUSCH provides ┌log₂(N_(RB) ^(UL)(N_(RB) ^(UL)+1)/2)┐ bitsfor resource allocation of the first slot in an uplink subframe. Here,N_(RB) ^(UL) denotes the number of RBs included in an uplink slot anddepends upon an uplink transmission bandwidth set in a cell.Accordingly, the payload size of DCI format 0 may depend upon uplinkbandwidth. DCI format 1A includes an information field for PDSCHallocation. The payload size of DCI format 1A may depend upon downlinkbandwidth. DCI format 1A provides a reference information bit size forDCI format 0. Accordingly, DCI format 0 is padded with ‘0’ until thepayload size of DCI format 0 becomes identical to the payload size ofDCI format 1A when the number of information bits of DCI format 0 isless than the number of information bits of DCI format 1A. The added ‘0’is filled in a padding field of DCI format.

The TPC field includes a power control command or value for PUSCHtransmission, PUCCH transmission, or PRACH transmission at a UE. The TPCfield is given by an absolute value or a relative value. The relativevalue may be accumulated to the current value of transmission power.When the current value of transmission power is the maximum transmissionpower of UE, a positive value of TPC may not be accumulated. When thecurrent value of transmission power is the minimum transmission power ofUE, a negative value of TPC may not be accumulated.

A base station determines a PDCCH format according to DCI to betransmitted to a UE, and attaches a cyclic redundancy check (CRC) tocontrol information. The CRC is masked with an identifier (e.g. a radionetwork temporary identifier (RNTI)) according to an owner or usage ofthe PDCCH. For example, if the PDCCH is for a specific UE, an identifier(e.g., cell-RNTI (C-RNTI)) of the UE may be masked to the CRC.Alternatively, if the PDCCH is for a paging message, a paging identifier(e.g., paging-RNTI (P-RNTI)) may be masked to the CRC. If the PDCCH isfor system information (more specifically, a system information block(SIB)), a system information RNTI (SI-RNTI) may be masked to the CRC.When the PDCCH is for a random access response, a random access-RNTI(RA-RNTI) may be masked to the CRC.

A plurality of PDCCHs may be transmitted within one subframe. A UE maymonitor the plurality of PDCCHs. PDCCH is transmitted on an aggregationof one or several consecutive control channel elements (CCEs). A CCE isa logical allocation unit used to provide the PDCCH with a coding ratebased on a state of a radio channel. The CCE corresponds to a pluralityof resource element groups (REGs).

The LTE(-A) system defines a limited set of CCE positions in which aPDCCH is to be positioned for each UE. The limited set of CCE positionsthat a UE can find a PDCCH of the UE may be referred to as a searchspace (SS). In the LTE(-A) system, the search space has different sizesaccording to each PDCCH format. In addition, a UE-specific search spaceand a common search space are separately defined. The base station doesnot provide the UE with information indicating where the PDCCH islocated in the control region. Accordingly, the UE monitors a set ofPDCCH candidates within the subframe and finds its own PDCCH. The term“monitoring” means that the UE attempts to decode the received PDCCHsaccording to respective DCI formats. The monitoring for a PDCCH in asearch space is referred to as blind decoding (or blind detection).Through blind decoding, the UE simultaneously performs identification ofthe PDCCH transmitted to the UE and decoding of the control informationtransmitted through the corresponding PDCCH. For example, if a CRC erroris not detected when the PDCCH is de-masked using the C-RNTI, the UE hasdetected its own PDCCH. The UE-specific search space (USS) is separatelyconfigured for each UE and a scope of common search space (CSS) is knownto all UEs. The USS and the CSS may be overlapped with each other.

To appropriately control computational load of blind decoding, the UE isnot required to simultaneously search for all defined DCI formats. Ingeneral, the UE always searches for formats 0 and 1A in USS. Formats 0and 1A have the same size and are discriminated from each other by aflag in a message. The UE may need to receive an additional format (e.g.format 1, 1B or 2 according to PDSCH transmission mode configured by abase station). The UE searches for formats 1A and 1C in CSS.Furthermore, the UE may be configured to search for format 3 or 3A.Formats 3 and 3A have the same size as that of formats 0 and 1A and maybe discriminated from each other by scrambling CRC with different(common) identifiers rather than a UE-specific identifier. A PDSCHtransmission scheme and information contents of DCI formats according toa transmission mode will be listed below.

Transmission Mode (TM)

-   -   Transmission Mode 1: Transmission from a single eNB antenna port    -   Transmission Mode 2: Transmit diversity    -   Transmission Mode 3: Open-loop spatial multiplexing    -   Transmission Mode 4: Closed-loop spatial multiplexing    -   Transmission Mode 5: Multi-user MIMO    -   Transmission Mode 6: Closed-loop rank-1 precoding    -   Transmission Mode 7: Single-antenna port (port 5) transmission    -   Transmission Mode 8: Dual layer transmission (ports 7 and 8) or        single-antenna port (port 7 or 8) transmission    -   Transmission Modes 9 and 10: Layer transmission up to rank 8        (ports 7 to 14) or single-antenna port (port 7 or 8)        transmission

DCI Format

-   -   Format 0: Resource grant for PUSCH transmission (uplink)    -   Format 1: Resource allocation for single codeword PUSCH        transmission (transmission modes 1, 2, and 7)    -   Format 1A: Compact signaling of resource allocation for single        codeword PDSCH transmission (all modes)    -   Format 1B: Compact resource allocation for PDSCH (mode 6) using        rank-1 closed-loop precoding    -   Format 1C: Very compact resource allocation for PDSCH (e.g.,        paging/broadcast system information)    -   Format 1D: Compact resource allocation for PDSCH (mode 5) using        multi-user MIMO    -   Format 2: Resource allocation for PDSCH (mode 4) of closed-loop        MIMO operation    -   Format 2A: Resource allocation for PDSCH (mode 3) of open-loop        MIMO operation    -   Format 3/3A: Power control command with 2-bit/1-bit power        adjustments for PUCCH and PUSCH    -   Format 4: Resource grant for PUSCH transmission (uplink) in a        cell configured in a multi-antenna port transmission mode

A UE may be semi-statically configured via higher layer signaling toreceive PDSCH data transmission that is scheduled by the PDCCH accordingto 10 transmission modes.

When a packet is transmitted in a wireless communication system, signaldistortion may occur during transmission since the signal is transmittedthrough a radio channel. To correctly receive a distorted signal at areceiver, the distorted signal needs to be corrected using channelinformation. To detect channel information, a signal known to both atransmitter and the receiver is transmitted and channel information isdetected with a degree of distortion of the signal when the signal isreceived through a channel. This signal is referred to as a pilot signalor a reference signal.

When data is transmitted/received using multiple antennas, the receivercan receive a correct signal only when the receiver is aware of achannel state between each transmit antenna and each receive antenna.Accordingly, a reference signal needs to be provided per transmitantenna, more specifically, per antenna port.

Reference signals may be classified into a reference signal foracquiring channel information and a reference signal used for datademodulation. The former is for a UE to acquire channel information indownlink, the reference signal for acquiring channel information istransmitted in wideband, and a UE which does not receive downlink datain a specific subframe receives the reference signal. Further, thisreference signal is used in a handover situation. The latter is areference signal transmitted together when a base station transmits adownlink signal, and enables a UE to demodulate the downlink signalusing the reference signal. The reference signal used for datademodulation is required to be transmitted in a data transmissionregion. For example, downlink reference signal includes:

-   -   i) a cell-specific reference signal (CRS) shared by all UEs in a        cell;    -   ii) a UE-specific reference signal for a specific UE only;    -   iii) a demodulation reference signal (DM-RS) transmitted for        coherent demodulation when a PDSCH is transmitted;    -   iv) a channel state information reference signal (CSI-RS) for        delivering channel state information (CSI) when a downlink DMRS        is transmitted;    -   v) a multimedia broadcast single frequency network (MBSFN)        reference signal transmitted for coherent demodulation of a        signal transmitted in MBSFN mode; and    -   vi) a positioning reference signal used to estimate geographic        position information of a UE.

FIG. 6 illustrates an example of allocating E-PDCCH in a subframe. Asdescribed above with reference to FIG. 4 and FIG. 5, first n number ofOFDM symbols of a subframe are used to transmit PDCCH, PHICH, PCFICH andthe like corresponding to physical channels configured to transmitvarious control information and the rest of OFDM symbols are used totransmit PDSCH in LTE (-A) system. However, LTE system after LTE release11 has a limited capability for PDSCH transmission because OFDM symbolsare limited due to PDCCH performance decrease resulting from lack ofPDCCH capability and inter-cell interference in case of coordinatemulti-point (CoMP), multi user-multiple input multiple output (MU-MIMO).Hence, a system (e.g., a system appearing after 3GPP TS 36 seriesrelease 11) appearing after LTE (-A) is introducing an enhanced PDCCH(E-PDCCH), which is multiplexed with PDSCH in a data region.

Referring to FIG. 6, a PDCCH (for convenience, legacy PDCCH or L-PDCCH)used in the LTE(-A) system may be allocated to a control region of asubframe. In the figure, an L-PDCCH region refers to a region to whichthe legacy PDCCH is allocated. In the context, the L-PDCCH region mayrefer to a control region, a control channel resource region (i.e., aCCE resource) to which a PDCCH can be actually allocated, or a PDCCHsearch space. A PDCCH may be additionally allocated in a data region(e.g., a resource region for a PDSCH, refer to FIG. 5). The PDCCHallocated to the data region is referred to as an E-PDCCH. Asillustrated, a channel resource may be additionally ensured through theE-PDCCH to alleviate scheduling restrictions due to limited controlchannel resource of an L-PDCCH region.

In detail, the E-PDCCH may be detected/demodulated based on a DM-RS. TheE-PDCCH may be configured to be transmitted over a PRB pair on a timeaxis. In more detail, a search space (SS) for E-PDCCH detection may beconfigured with one or more (e.g., 2) E-PDCCH candidate sets. EachE-PDCCH set may occupy a plurality of (e.g., 2, 4, or 8) PRB pairs. Anenhanced-CCE (E-CCE) constructing an E-PDCCH set may be mapped in thelocalized or distributed form (according to whether one E-CCE isdistributed in a plurality of PRB pairs). In addition, when E-PDCCHbased scheduling is configured, a subframe for transmission/detection ofan E-PDCCH may be designated. The E-PDCCH may be configured in only aUSS. The UE may attempt DCI detection only on an L-PDCCH CSS and anE-PDCCH USS in a subframe (hereinafter, an E-PDCCH subframe) in whichE-PDCCH transmission/detection is configured and attempt DCI detectionon an L-PDCCH CSS and an L-PDCCH USS in a subframe (non-E-PDCCHsubframe) in which transmission/detection of E-PDCCH is not configured.

Like an L-PDCCH, an E-PDCCH carries DCI. For example, the E-PDCCH maycarry DL scheduling information and UL scheduling information. AnE-PDCCH/PDSCH procedure and an E-PDCCH/PUSCH procedure are thesame/similar to in steps S207 and S208 of FIG. 2. That is, a UE mayreceive the E-PDCCH and receive data/control information through a PDSCHcorresponding to the E-PDCCH. In addition, the UE may receive theE-PDCCH and transmit data/control information through a PUSCHcorresponding to the E-PDCCH. The LTE(-A) system pre-reserves a PDCCHcandidate region (hereinafter, a PDCCH search space) in a control regionand transmits a PDCCH of a specific UE to a partial region of the PDCCHcandidate region. Accordingly, the UE may acquire a PDCCH of the UE inthe PDCCH search space via blind decoding. Similarly, the E-PDCCH may betransmitted over a partial or entire portion of a pre-reserved resource.

In the meantime, in a long term evolution-advanced (LTE-A) system, amultimedia broadcast multicast service single frequency network(MBSFN)-based multimedia broadcast and multimedia service (MBMS) isdefined in order to provide a broadcast service over a communicationnetwork. An MBSFN is technology for simultaneously transmitting the samedata at the same time in all of nodes belonging to an MBSFN area insynchronization with a radio resource. Here, the MBSFN area refers to anarea covered by one MBSFN. According to the MBSFN, even when the UE islocated at an edge of coverage of a node that the UE has accessed, asignal of a neighboring node functions not as interference but as gain.That is, the MBSFN introduces a single frequency network (SFN) functionfor MBMS transmission, thereby reducing service interference caused byfrequency switching in the middle of MBMS transmission. Therefore, theUE within the MBSFN area recognizes MBMS data transmitted by multiplenodes as data transmitted by one node and in this MBSFN area, the UE mayreceive a seamless broadcast service without an additional handoverprocedure even while in motion. In the MBSFN, since a plurality of nodesuse a single frequency in order to simultaneously perform synchronizedtransmission, frequency resources can be saved and spectrum efficiencycan be raised.

Meanwhile, in a 3GPP LTE(-A) system (e.g., Release-8, 9, or 10), a CRSand a control channel such as a PCFICH/PDCCH/PHICH may be transmitted inevery DL subframe of a carrier, except a DL subframe configured for aspecial purpose (e.g., as an MBSFN subframe). The CRS may be allocatedacross OFDM symbols of a subframe and the control channel such as aPCFICH/PDCCH/PHICH may be allocated to some starting OFDM symbols of asubframe in time. The CRS and the control channels may ensure backwardcompatibility for legacy UEs in terms of connection and serviceprovisioning. However, it may be difficult to overcome inter-cellinterference, improve carrier extension, and provide advanced features,while maintaining backward compatibility with the legacy LTE system.Accordingly, introduction of a new carrier, subframe, or TM structurethat supports none or a part of the afore-described backward compatiblesignals/channels may be considered in order to provide various advancedfeatures compared to the legacy LTE system, in a next-release system. Acarrier type that is not compatible with the legacy LTE system may bereferred to as a New Carrier Type (NCT), and a carrier compatible withthe legacy LTE(-A) system may be referred to as a Legacy Carrier Type(LCT).

FIG. 7 illustrates a structure of an uplink subframe.

Referring to FIG. 7, the uplink subframe includes a plurality of slots(for example, two). Each slot may include a plurality of SC-FDMAsymbols, wherein the number of SC-FDMA symbols included in each slot isvaried depending on a cyclic prefix (CP) length. In an example, a slotmay comprise 7 SC-FDMA symbols in case of normal CP, and a slot maycomprise 6 SC-FDMA symbols in case of extended CP. An uplink subframe isdivided into a data region and a control region. The data regionincludes a PUSCH, and is used to transmit a data signal that includesvoice information. The control region includes a PUCCH, and is used totransmit uplink control information (UCI). The PUCCH includes RB pair(e.g. m=0, 1, 2, 3) located at both ends of the data region on afrequency axis (e.g. RB pair located frequency mirrored positions), andperforms hopping on the border of the slots. The uplink controlinformation (UCI) includes HARQ ACK/NACK, CQI (Channel QualityIndicator), a precoding matrix indicator (PMI), a rank indicator (RI),etc.

SRS (Sounding Reference Signal) is transmitted at the last SC-FDMAsymbol of a subframe. SRS may be transmitted periodically, or may betransmitted aperiodically according to a request of a base station.Periodic SRS transmission is defined by a cell-specific parameter and aUE-specific parameter. The cell-specific parameter notifies an entiresubframe set (hereinafter, cell-specific SRS subframe set) available forSRS transmission within a cell, and the UE-specific parameter notifies asubframe sub-set (hereinafter, UE-specific SRS subframe set) actuallyallocated to a UE within the entire subframe set.

A legacy LTE (Rel-8/9) and LTE-A (Rel-10/11) system may schedule onlyone DL/UL data from one DL/UL grant downlink control information (DCI)and employs a scheme of transmitting corresponding DL/UL data throughone DL/UL subframe (i.e., a SF). In this specification, this schedulingmethod may be referred to as a single-SF scheduling. A future system mayconsider a multi-SF scheduling method for simultaneously scheduling aplurality of DL/UL data from one DL/UL grant DCI in order to enhancespectral efficiency, and in the multi-SF scheduling method, theplurality of corresponding DL/UL data may be configured to besequentially transmitted through a plurality of DL/UL SFs.

The present invention proposes a control signaling method for multi-SFscheduling. In detail, the present invention proposes DL relatedconfiguration method and a DCI transmitting method for multi-SFscheduling according to a radio frame type (e.g., FDD or TDD). First,for convenience of description of the present invention, terms used inthe specification are defined as follows.

-   -   multi-SF window: K (e.g., K>1) subframes (SFs) directed to        multi-SF scheduling    -   multi-SF DCI: DCI scheduling a multi-SF window    -   starting SF: a subframe (SF) in which multi-SF DCI is        detected/received (or a specific SF after multi-SF DCI is        detected/received)    -   indicated O-SF: a specific subframe (SF) that is directly        indicated from multi-SF DCI (as a target to which scheduling is        not applied)

For convenience of description, although the present invention has beendescribed in terms of downlink multi-SF scheduling, the presentinvention may be applied to uplink multi-SF scheduling in the same way.

A multi-SF window may include K consecutive subframes (SFs) including astarting SF. In this case, the K consecutive subframes may have one SFinterval or one or more H (e.g., H>1) SF interval. For example, when twoconsecutive subframes include SF #n and SF #n+1, it may be said that thetwo consecutive subframes have one subframe (SF) interval. As anotherexample, when two consecutive subframes include SF #n and SF #n+2, itmay be said that the two consecutive subframes have a two SF interval.

In this case, the multi-SF window may include K consecutive SFs (or theremaining K or less SFs except for an indicated O-SF there among) exceptfor SFs (all or some SFs) having the following special purpose orspecific aspect from a starting SF, and such a scheme may be referred toas “SF-skipping”. Alternatively, the multi-SF window may include onlythe remaining K or less SFs except for SFs (all or some SFs) having thefollowing special purpose or specific aspect and/or an indicated O-SFamong K consecutive SFs from a starting SF, and such a scheme may bereferred to as “SF-omitting”. For example, a SF having the followingspecial purpose or specific aspect may refer to a SF corresponding to atleast one of {circle around (1)} to {circle around (10)} and may bereferred to as “special X-SF” in this specification.

{circle around (1)} SF configured for a multicast-broadcastsingle-frequency network (MBSFN) and/or SF configured to detect/receivea physical multicast channel (PMCH). The PMCH refers to a physicalchannel for carrying a multicast data signal.

{circle around (2)} SF in which a physical broadcast channel (PBCH)and/or (specific) system information block (SIB) and/or a paging signalare transmitted. In detail, the SF may correspond to the special X-SFonly when a resource region allocated through multi-SF DCI is overlappedwith a resource (e.g., a resource block (RB)) occupied by a PBCH and/ora (specific) SIB and/or a paging signal. The PBCH refers to a physicalchannel for carrying a broadcast data signal.

{circle around (3)} SF in which a synchronization signal such as aprimary synchronization signal (PSS) and/or a secondary synchronizationsignal (SSS) is transmitted. In detail, the SF may correspond to thespecial X-SF only when a resource region allocated through multi-SF DCIis overlapped with a resource (e.g., a resource block (RB)) occupied bya synchronization signal such as a PSS and/or a SSS. The PSS may betransmitted through a P-SCH and the SSS may be transmitted through theS-SCH.

{circle around (4)} SF in which transmitted PDSCH/PUSCH schedulingwithout corresponding PDCCH/EPDCCH is performed (or reserved). Forexample, SF in which data transmission and reception is performed basedon scheduling based on semi-persistent scheduling (SPS).

{circle around (5)} SF that performs (or is configured to be availablefor) PRACH transmission.

{circle around (6)} SF that performs (or is configured to perform)positioning reference signal (PRS) transmission.

{circle around (7)} All or specific TDD special SF (a downlink period(e.g., DwPTS) of which is configured with L or less symbols and/or inwhich DMRS is not transmitted). For example, L may be 3.

{circle around (8)} SF that perform (or is configured to perform)transmission of a common RS for synchronization tracking and/or adiscovery signal for cell/UE in a new carrier type (in which CRSs arenot consecutively transmitted). In detail, the SF may correspond to onlythe case in which a resource region allocated through multi-SF DCI isoverlapped with a resource (e.g., a resource block (RB)) occupied by acommon RS for tracking and/or a discovery signal.

{circle around (9)} SF that does not transmit (or is configured not totransmit) DMRS.

{circle around (10)} SF that performs (or is configured to perform)transmission of non-zero power and/or zero-power CSI-RS).

A legacy single-SF scheduling method may be applied to an entire orspecific partial portion of a special X-SF or an indicated O-SF.

When an interval between an SF in which multi-SF DCI isdetected/received and a corresponding starting SF is S, K (and/or H)and/or S may be pre-set through high layer signaling (e.g., RRCsignaling) and so on (e.g., K>1, H≥1, S≥0). In addition, whether amulti-SF window configured with K SFs is scheduled or one subframe (SF)is scheduled as a target of scheduling of the corresponding DCI may besignaled through the multi-SF DCI.

FIG. 8 illustrates a multi-SF scheduling method according to the presentinvention. FIG. 8(A) illustrates a multi-SF scheduling method accordingto a SF-skipping method, and FIG. 8(B) illustrates a multi-SF schedulingmethod according to a SF-omitting method.

Referring to FIGS. 8(A), K, H, and S may be pre-configured through highlayer signaling (e.g., RRC signaling) and so on. Multi-SF DCI may bedetected/received in a subframe SF #n and may include informationindicating that a multi-SF window comprising K SFs is scheduled. In thiscase, the multi-SF window may start from a SF #(n+S) and may have aninterval H. In the example of FIG. 8(A), a m^(th) subframe SF#(n+S+(m−1)*H) in the multi-SF window may correspond to a special-X SFand/or an indicated-O SF. In this case, according to the SF-skippingmethod, the multi-SF window may include K subframes except for subframescorresponding to the special-X SF and/or the indicated-O SF.Accordingly, in the example of FIG. 8(A), the multi-SF window mayinclude subframes from SF #(n+S) to SF #(n+S+K*H) with an interval Hexcept for SF #(n+S+(m−1)*H).

On the other hand, referring to FIG. 8(B), the multi-SF window mayinclude K subframes including a m^(th) subframe SF #(n+S+(m−1)*H) in themulti-SF window. Accordingly, according to the SF-omitting method, themulti-SF window may include subframes from SF #(n+S) to SF#(n+S+(K−1)*H) with an interval H including SF #(n+S+(m−1)*H).

Although the case in which S and H are pre-configured via high layersignaling has been described thus far, S or H may be fixed to a specificvalue. For example, S may be fixed to a specific integer equal to orgreater than 0, and only K and H may be configured through high layersignaling (e.g., RRC signaling). As another example, H may be fixed to aspecific integer equal to or greater than 1, and only K and S may beconfigured via high layer singling (e.g., RRC signaling). As anotherexample, K and H may be fixed to a specific integer equal to or greaterthan 0, and a specific integer equal to or greater than 1 and only K maybe configured via high layer signaling (e.g., RRC signaling).

FIG. 9 illustrates a flowchart of a method for receiving data accordingto the present invention.

Referring to FIG. 9, in S902, a UE may detect/receive downlink controlinformation including scheduling information about a plurality ofsubframes. The number of the plurality of subframes may be indicated byK (e.g., K>1). The downlink control information may be detected/receivedthrough a physical downlink control channel.

When at least one of the plurality of subframes is a special X-SF (e.g.,a subframe corresponding to at least one of {circle around (1)} to{circle around (10)}), the scheduling information may not be applied tothe at least one subframe. Accordingly, in this case, a receptionoperation of a data signal using the scheduling information may beomitted. Similarly, when at least one subframe among the plurality ofsubframes corresponds to an indicated-O SF, the scheduling informationmay not be applied to the at least one subframe. Accordingly, in thiscase, a reception operation using the scheduling operation may also beomitted. A subframe in which the reception operation of the data signalusing the scheduling information is omitted may be referred to as anomitted subframe, for convenience.

In S904, the UE may receive a data signal using the schedulinginformation in M subframes except for the omitted subframe. In thiscase, M may be equal to or less than K according to whether the omittedsubframe is present.

In FIG. 9, when the SF-skipping method is applied, the schedulinginformation may be applied to K subframes (or data signalsreceived/detected from K subframes) except for the omitted subframe.Alternatively, when the SF-omitting method is applied, the schedulinginformation may be applied to M subframes (or data signalsreceived/detected from M subframes) except for the omitted subframe.When the SF-omitting method is applied, M may have a value smaller thanK.

Different HARQ process numbers may be allocated to data signalsscheduled by the multi-SF DCI. A plurality of parallel HARQ processesfor UL/DL transmission are present in the UE. The plurality of parallelHARQ processes may be performed by consecutively performing UL/DLtransmission while waiting for HARQ feedback with respect to successfulor non-successful reception of previous UL/DL transmission. Each HARQprocess is associated with a HARQ buffer of a medium access control(MAC) layer. Each HARQ process manages a state variable related to atransmission number of times of MAC physical data block (PDU) in abuffer, HARQ feedback with respect to the MAC PDU in the buffer, acurrent redundancy version, and so on. For example, in the case ofLTE(-A) FDD, the number of HARQ processes for a non-subframe bundlingoperation (i.e., a general HARQ operation) is 8. In the case of LTE(-A)TDD, since the number of subframes is varied according to a UL-DLconfiguration, the number of HARQ processes and HARQ round trip time(RTT) are also configured to be varied according to a UL-DLconfiguration. Here, the HARQ RTT may refer to a time interval (e.g., aunit of SF or ms) from a reception time point of UL grant to a receptiontime point of a (corresponding) PHICH through (corresponding) PUSCHtransmission, or a time interval from a transmission time point of aPUSCH to a corresponding retransmission time point.

In order to signal K HARQ process numbers (or HARQp nums) allocated to Kdata scheduled through multi-SF DCI, one of the following methods may beapplied.

Alt-1) K HARQ process numbers (HARQp nums) for multi-SF scheduling arepre-allocated via high layer signaling (e.g., RRC signaling) and so on.

Alt-2) The K HARQ process numbers (HARQp nums) are directly allocatedthrough a legacy HARQ process number (HARQp num) field in the multi-SFDCI or a combination of specific fields including the legacy HARQprocess number (HARQp num) field or by adding a new field to themulti-SF DCI.

In Alt-2, when the K HARQ process numbers (HARQp nums) for multi-SFscheduling are allocated using the legacy HARQ process number (HARQpnum) field, K cyclically consecutive HARQ process numbers (HARQp nums)may be allocated. For example, assuming that a value signaled throughthe HARQ process number (HARQp num) field is P, the K cyclicallyconsecutive HARQp nums may be allocated using the following method.

-   -   HARQ process number (HARQp num) allocated to a first SF (or        data): (P) mod maxHARQp    -   HARQ process number (HARQp num) allocated to a second SF (or        data): (P+1) mod maxHARQp    -   . . .    -   HARQ process number (HARQp num) allocated to a K^(th) SF (or        data): (P+K−1) mod maxHARQp

In the above method, maxHARQp may refer to a maximum number of HARQprocesses (HARQp) (supportable by a UE), the number of receive buffersof HARQ process (HARQp), or the number of HARQ processes (HARQp)determined for multi-SF scheduling. Accordingly, the HARQ process number(HARQp num) may have a value from 0 to (maxHARQp−1). In addition, in theabove method, mod refers to modulo operation.

In Alt-2, when the HARQ process number (HARQp num) for multi-SFscheduling is allocated using a combination of specific fields in themulti-SF DCI or using a newly added field, K HARQ process numbers (HARQpnums) may be signaled using a combinatorial index. Here, the HARQprocess number (HARQp num) may be assumed to have a value from 1 tomaxHARQp.

Assuming that a set {k_(i)}_(i=0) ^(K−1), (1≤k_(i)≤maxHARQp,k_(i)<k_(i+1)) has K aligned HARQp numbers and

$\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle = \left\{ {\begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix},} \right.$indicates a extended binomial coefficient, K selected HARQp numbers areindicated using a combinatorial index r defined as

$r = {{\sum\limits_{i = 0}^{K - 1}{\left\langle \begin{matrix}{{\max\;{HARQp}} - k_{i}} \\{K - i}\end{matrix} \right\rangle\mspace{14mu}{and}\mspace{14mu} r}} \in \left\{ {0,\ldots\mspace{14mu},{\begin{pmatrix}{\max\;{HARQp}} \\K\end{pmatrix} - 1}} \right\}}$has a unique value for the K selected HARQp numbers (K selected HARQpnumbers using a combinatorial index r defined as

${r = {\sum\limits_{i = 0}^{K - 1}\left\langle \begin{matrix}{{\max\;{HARQp}} - k_{i}} \\{K - i}\end{matrix} \right\rangle}},$where the set {k_(i)}_(i=0) ^(K−1), (1≤k_(i)≤maxHARQp, k_(i)<k_(i+1))contains the K sorted HARQp numbers and

$\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle = \left\{ {\begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix},} \right.$is the extended binomial coefficient, resulting in unique label

$\left. {r \in \left\{ {0,\ldots\mspace{14mu},{\begin{pmatrix}{\max\;{HARQp}} \\K\end{pmatrix} - 1}} \right\}} \right).$

That is, the set {k_(i)}_(i=0) ^(K−1) of the K HARM process numbers maybe uniquely represented by a combinatorial index

$r = {\sum\limits_{i = 0}^{K - 1}{\left\langle \begin{matrix}{{\max\;{HARQp}} - k_{i}} \\{K - i}\end{matrix} \right\rangle.}}$A binominal coefficient

$\quad\begin{pmatrix}x \\y\end{pmatrix}$may be represented by xCy.

FIG. 10 illustrates an example of allocating HARQ process numbers usinga combinatorial index. FIG. 10 illustrates, but is not limited to, anexample in which maxHARQp is 10 and K=4. In FIG. 10, a binominalcoefficient is represented by comb(x, y).

Referring to FIG. 10, a set {2, 3, 5, 8} of HARQ process numbers may beuniquely represented by a combinatorial index

$r = {\sum\limits_{i = 0}^{K - 1}{\left\langle \begin{matrix}{{\max\;{HARQp}} - k_{i}} \\{K - i}\end{matrix} \right\rangle.}}$In the example of FIG. 10, since maxHARQp=10 and K=4, the set may beuniquely represented by r=₈C₄+₇C₃+₅C₂+₂C₁=70+35+10+2=117. A set havingother HARQ process numbers as elements may be uniquely represented byanother combinatorial index.

In Alt-2, when a HARQ process number (HARQp num) for multi-SF schedulingis allocated using a combination of specific fields in a multi-SF DCI,the combination of specific fields may consider the following method.

Sol-1) HARQ Process Number (HARQp Num) Field+Redundancy Version (RV)Field.

This method may be applied to TM-common DCI (e.g., DCI format 1A) forscheduling only maximum one transport block (TB) per SF. In detail,while a RV pattern for initial transmission and retransmission ofmulti-SF scheduled data is pre-configured (via high layer signaling(e.g., RRC signaling) and so on), a HARQ process number (HARQp num)field in DCI format and an RV field may be combined to allocate the HARQprocess number (HARQp num) for the multi-SF scheduled data. In thiscase, since the RV pattern is pre-configured, the RV field indicating RVmay be used to allocate the HARQ process number (HARQp num).

Sol-2) HARQ Process Number (HARQp Num) Field+MCS and/or RV Field.

This method may be applied to TM-dedicated DCI (e.g., DCI format 2C/2D)for scheduling maximum two transport blocks (TBs) per SF. For example,when HARQp num/MCS/RV fields corresponding to TB1 and TB2 in DCI formatare referred to as HARQ1/MCS1/RV1 and HARQ2/MCS2/RV2, respectively, MCSand/or RV values signaled through MCS1 and/or RV1 fields may be commonlyapplied in the same way to a plurality of multi-SF scheduled transportblocks (TBs), and HARQ1/HARQ2 fields and MCS2 and/or RV2 fields may becombine to allocate HARQp num for a plurality of multi-SF scheduledtransport blocks TBs. As another example, MCS and/or RV values signaledthrough MCS2 and/or RV2 fields may be commonly applied in the same wayto a plurality of multi-SF scheduled transport blocks (TBs), andHARQ1/HARQ2 fields and MCS1 and/or RV1 fields may be combined toallocate HARQp num for a plurality of multi-SF scheduled transportblocks TBs.

When the SF-skipping method, the SF-omitting method, or the like isapplied, only M (M<K) SFs/data may be scheduled through the multi-SFDCI. In this case, only M HARQ process numbers (HARQp nums) may beselected and allocated among K HARQ process numbers (HARQp nums)determined by applying the above methods (Alt-1 or Alt-2). As a firstexample, M specific HARQ process numbers (HARQp nums) among K HARQprocess numbers (HARQp nums) may be sequentially allocated to MSFs/data. In more detail, HARQ process numbers (HARQp nums)corresponding to first to M^(th) SFs/data among K HARQ process numbersmay be sequentially allocated. As a second example, the remaining M HARQprocess numbers (HARQp nums) except for HARQ process numbers (HARQpnums) corresponding to (K−M) omitted SFs among K HARQ process numbers(HARQp nums) may be sequentially allocated.

FIG. 11 illustrates an example of allocating a HARQ process when anomitted SF is present. FIG. 11 assumes, but is not limited to, anexample in which K=4 and a third subframe corresponds to an omitted SF.Accordingly, in the example of FIG. 11, it is assumed that M=3.

Referring to FIG. 11(A), according to the first example, M HARQ processnumbers (HARQp nums) among K HARQ process numbers (HARQp nums) may besequentially allocated. For example, when a set of four HARQ processnumbers (HARQp nums) is determined as {1, 2, 3, 4}, HARQ process numbers(HARQp nums) 1, 2, and 3 corresponding to first to third SFs/data may besequentially allocated to subframes except for the omitted SF. A HARQprocess number (HARQp num) of a last subframe in the multi-SF window maybe 3.

Referring to FIG. 11(B), according to the second example, M HARQ processnumbers (HARQp nums) among K HARQ process numbers (HARQp nums) may besequentially allocated. For example, when a set of 4 HARQ processnumbers (HARQp nums) is determined as {1, 2, 3, 4}, three HARQ processnumbers (HARQp nums) 1, 2, and 4 corresponding to first, second, andfourth SFs (or data) except for a HARQ process number (HARQp num) 3corresponding to the omitted SF may be allocated to subframes in themulti-SF window. Accordingly, a HARQ process number (HARQp num) of alast subframe in the multi-SF window may be 4.

A field configuration and/or size, etc. of the multi-SF DCI may beconfigured differently from legacy DCI format through the above methodor other methods. Accordingly, in order to prevent a increase of blinddecoding due to the difference and/or allow an appropriateinterpretation of multi-SF DCI fields, a SF in which a blind decoding(BD) is to be performed on the multi-SF DCI may be signaled through highlayer signaling (e.g., RRC signaling) and so on. In detail, whendetection/reception of the multi-SF DCI is successful, BD may be appliedaccording to one of the following methods with respect to a multi-SFwindow period corresponding to the corresponding DCI (except for the SFin which the corresponding DCI is detected/received).

A-1) BD may be omitted.

A-2) BD may be performed on DCI (single-SF DCI) for performing single-SFscheduling. In this case, when the single-SF DCI is detected/received ina multi-SF scheduled multi-SF window, a method A-2-1 or A-2-2 may beapplied.

A-2-1) Only data corresponding to a SF in which corresponding DCI isdetected/received in the multi-SF window may be replaced to be scheduledthrough the corresponding DCI.

A-2-2) Data corresponding to a SF in which corresponding DCI isdetected/received in the multi-SF window may be replaced to be scheduledthrough the corresponding DCI and a detection/reception operation ofdata corresponding to a next SF may be omitted. In the case of A-2-2,when separate additional DCI detection/reception for scheduling a nextSF is not present, an A/N response corresponding thereto may beprocessed as DTX or NACK.

In A-2-1 and A-2-2, the operation in which “data corresponding to a SFin which a single subframe (single-SF) DCI is detected/received in themulti-SF window is replaced to be scheduled through the correspondingDCI” may refer to performing detection/reception of data scheduled fromsingle-SF DCI instead of omission of detection/reception of datascheduled from multi-SF DCI in the corresponding SF. For convenience ofdescription, when a HARQ process number (HARQp num) allocated to an SFthrough multi-SF DCI/scheduling is referred to as “mHARQp num” and aHARQ process number (HARQp num) allocated to a corresponding SF throughsingle-SF DCI/scheduling is referred to as “sHARQp num”, the operationmay refer to storing/combining of corresponding data to a receive buffercorresponding to the sHARQp num without storing/combining of thecorresponding data to a receive buffer corresponding to the mHARQp num.

Similarly, in A-2-1 and A-2-2, an operation in which“detection/reception of data corresponding to SF(s) after a time pointfor detection/reception of single-SF DCI is omitted” may refer to anoperation in which detection/reception of data scheduled from multi-SFDCI in the corresponding SF(s) is omitted. That is, the operation mayrefer to an operation in which corresponding data is not stored/combinedin a receive buffer corresponding to mHARQp num allocated tocorresponding SF(s).

While EPDCCH-based scheduling is configured, a situation in which otherDCI is detected/received through an EPDCCH region overlapped with a DLdata region scheduled from multi-SF DCI in a specific SF in a multi-SFwindow may be considered. In this case, when the DCI detected/receivedthrough the EPDCCH region overlapped with the DL data region scheduledfrom the multi-SF DCI is DL grant, the above operation (A-1 or A-2) maybe applied.

On the other hand, when the DCI detected/received through the EPDCCHregion overlapped with the DL data region scheduled from the multi-SFDCI is UL grant, application of one of the following methods may beconsidered.

B-1) A detection/reception operation may be omitted with respect to onlyDL data corresponding to an SF in which corresponding DCI isdetected/received in the multi-SF window (an A/N response correspondingthereto may be processed as DTX or NACK).

B-2) A detection/reception operation may be omitted with respect to allDL data corresponding to next SFs including a SF in which thecorresponding DCI is detected/received in the multi-SF window (an A/Nresponse corresponding thereto may be processed as DTX or NACK whenseparate additional detection/reception for scheduling the correspondingSF is not present).

B-3) A UE may operate with considering/assuming that UL grant (and/or DLgrant) is not transmitted/received through an EPDCCH region overlappedwith a DL data region scheduled from multi-SF DCI. Alternatively, BD maybe omitted with respect to the corresponding overlapped region.

B-4) A UL grant region may be punctured or rate-matched to transmit andreceive DL data.

In a situation in which EPDCCH-based scheduling is configured, if aregion of DL data (e.g., SPS PDSCH) transmitted without correspondingPDCCH/EPDCCH and an EPDCCH region are overlapped, the same/similarprinciple of B-1 to B-4 may also be applied during a detection/receptionoperation of DL data associated with the corresponding overlapped regionand DCI.

In a situation in which multi-SF scheduling and single-SF scheduling areselectively applied according to a SF, A/N feedback with respect to amulti-SF scheduled multi-SF window may have a remarkably increasedpayload/codebook size compared with A/N feedback corresponding tosingle-SF scheduling. Accordingly, in order to prevent coverage loss dueto this, it may be necessary to increase PUCCH transmission power by alarge amount. To this end, when multi-SF scheduling is configured, oneof the following methods may be applied to TPC signaled through multi-SFDCI (and/or single-SF DCI).

C-1) A legacy TPC field size (the number of TPC values) may bemaintained and a magnitude of a (entire or partial) legacy TPC value maybe increased.

C-2) A method for increasing a TPC field size (the number of TPC values)and additionally defining a TPC value (except for a legacy TPC value)having a greater magnitude than the legacy TPC value may be considered.

Multi-SF scheduling through a common search space (CSS) and/or usingTM-common DCI (e.g., DCI format 0/1A) may not be permitted. One of thefollowing methods may be applied to an aperiodic SRS request fieldand/or an aperiodic CSI request field.

D-1) The field may be interpreted/used for allocation of a HARQ processnumber (HARQp num) for the multi-SF scheduling. In this case, theaperiodic SRS/CSI request through the multi-SF DCI may not be permitted.

D-2) Aperiodic SRS/CSI request through the multi-SF DCI may be permittedand SRS transmission time point/CSI reporting time point correspondingthereto may be determined based on only a SF in which corresponding DCIis detected/received. In this case, when aperiodic SRS/CSI request isreceived through a corresponding SF, the UE may operate in the same wayas in a legacy case in which general single-SF DCI is detected/received.For example, aperiodic CSI reporting may be performed (e.g., only once)through an initial SF in a multi-SF window corresponding tocorresponding multi-SF DCI (including aperiodic CSI request). Inaddition, for example, aperiodic SRS transmission may be performed(e.g., only once) through an initial UE-specific aperiodic SRS SF setafter a SF (or a time point after several SFs from the SF) in whichcorresponding multi-SF DCI (including aperiodic SRS request) isdetected/received.

Although the present invention has been described in terms of a DL datasignal, the present invention may also be applied in the same/similarway to multi-SF scheduling with respect to a UL data signal. Forexample, a multi-SF window configuration, a multi-SF DCI BD procedure, aRRC/DCI signaling method, and so on may be similarly extended/modifiedto be applied to multi-SF scheduling of a UL data signal.

Some (e.g., a multi-SF window configuration and so on) of the methodsproposed according to the present invention may also be applied in thesame/similar way to a situation applying a multi-SF scheduling method inwhich one DL/UL data signal (e.g., the same data signal) scheduled fromone DL/UL grant DCI is repeatedly transmitted over a plurality ofspecific DL/UL SFs in order to enhance cell coverage.

FIG. 12 illustrates a base station and a user equipment to which thepresent invention is applicable.

Referring to FIG. 12, a wireless communication system includes the BS1210 and the UE 1220. When the wireless communication system includes arelay, the BS 1210 or the UE 1220 may be replaced with the relay.

The BS 1210 includes a processor 1212, a memory 1214, and a radiofrequency (RF) unit 1216. The processor 1212 may be configured to embodythe procedures and/or methods proposed by the present invention. Thememory 1214 is connected to the processor 1212 and stores various piecesof information associated with an operation of the processor 1212. TheRF unit 1216 is connected to the processor 1212 and transmits/receives aradio signal. The UE 1220 includes a process 1222, a memory 1224, and anRF unit 1226. The processor 1222 may be configured to embody theprocedures and/or methods proposed by the present invention. The memory1224 is connected to the processor 1222 and stores various pieces ofinformation associated with an operation of the processor 1222. The RFunit 1226 is connected to the processor 1222 and transmits/receives aradio signal.

The embodiments of the present invention described above arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It is obvious tothose skilled in the art that claims that are not explicitly cited ineach other in the appended claims may be presented in combination as anembodiment of the present invention or included as a new claim by asubsequent amendment after the application is filed.

Specific operations to be conducted by the base station in the presentinvention may also be conducted by an upper node of the base station asnecessary. In other words, it will be obvious to those skilled in theart that various operations for enabling the base station to communicatewith the terminal in a network composed of several network nodesincluding the base station will be conducted by the base station orother network nodes other than the base station.

The embodiments of the present invention may be implemented by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware implementation, an embodiment of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSDPs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

In a firmware or software implementation, an embodiment of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. Software code may be stored in a memory unit and executedby a processor. The memory unit is located at the interior or exteriorof the processor and may transmit and receive data to and from theprocessor via various known means.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The present invention is applicable to a wireless communicationapparatus such as a user equipment (UE), a base station (BS), etc.

What is claimed is:
 1. A method for receiving a signal by a userequipment in a wireless communication system, the method comprising:detecting downlink control information (DCI) within a subframe indicatedby a radio resource control (RRC) layer signal; and receiving, based onthe DCI, a data signal in K consecutive subframes other than at leastone subframe including a subframe transmitting a physical broadcastchannel (PBCH), a subframe transmitting a synchronization signal, and asubframe transmitting system information, wherein K is greater than 1,and wherein the DCI is not applied to the at least one subframe.
 2. Themethod according to claim 1, wherein the at least one subframe furtherincludes a subframe configured for a multicast-broadcastsingle-frequency network (MBSFN), or a subframe configured to transmit apaging signal, or a subframe configured to perform semi-persistentscheduling, or a subframe configured to enable transmission of aphysical random access channel (PRACH), or a subframe configured not totransmit a demodulation reference signal (DMRS), or a subframeconfigured to transmit a channel state information-reference signal(CSI-RS), or a subframe configured to receive a physical multicastchannel (PMCH), or a subframe transmitting a positioning referencesignal (PRS), or a subframe comprising a downlink period, a guardperiod, and an uplink period.
 3. The method according to claim 1,wherein the DCI indicates whether the DCI is applied to the Kconsecutive subframes or one subframe.
 4. The method according to claim1, wherein the synchronization signal includes a primary synchronizationsignal (PSS) and a secondary synchronization signal (SSS).
 5. The methodaccording to claim 1, wherein the DCI is detected through a physicaldownlink control channel.
 6. The method according to claim 1, whereineach of the data signals is received through a physical downlink sharedchannel.
 7. The method according to claim 1, wherein different hybridautomatic repeat request (HARQ) process numbers are allocated to thedata signals.
 8. The method according to claim 1, wherein, when anotherDCI is detected in one subframe of the K subframes, another data signalis received according to the another DCI in the one subframe.
 9. A userequipment operating in a wireless communication system, the userequipment comprising: a transceiver; and a processor configured to:detect downlink control information (DCI) within a subframe indicated bya radio resource control (RRC) layer signal, and control the transceiverto receive, based on the DCI, data signals in K consecutive subframesother than at least one subframe including a subframe transmitting aphysical broadcast channel (PBCH), a subframe transmitting asynchronization signal, and a subframe transmitting system information,wherein K is greater than 1, and wherein the DCI is not applied to theat least one subframe.
 10. The user equipment according to claim 9,wherein the at least one subframe further includes subframe configuredfor a multicast-broadcast single-frequency network (MBSFN), or asubframe configured to transmit a paging signal, or a subframeconfigured to perform semi-persistent scheduling, or a subframeconfigured to enable transmission of a physical random access channel(PRACH), or a subframe configured not to transmit a demodulationreference signal (DMRS), or a subframe configured to transmit a channelstate into signal (CSI-RS), or a subframe configured to receive aphysical multicast channel (PMCH), or a subframe transmitting apositioning reference signal (PRS), or a subframe comprising a downlinkperiod, a guard period, and an uplink period.
 11. The user equipmentaccording to claim 9, wherein the DCI indicates whether the DCI isapplied to the K consecutive subframes or one subframe.
 12. The userequipment according to claim 9, wherein the synchronization signalincludes a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS).
 13. The user equipment according to claim9, wherein the DCI is detected through a physical downlink controlchannel.
 14. The user equipment according to claim 9, wherein each ofthe data signals is received through a physical downlink shared channel.15. The user equipment according to claim 9, wherein different hybridautomatic repeat request (HARQ) process numbers are allocated to thesubframes other than the at least one subframe.
 16. The user equipmentaccording to claim 9, wherein, when another DCI is detected in onesubframe of the K subframes, another data signal is received accordingto the another DCI in the one subframe.